This summer we wake up every fourth morning or so to an email from Thailand or Laos. So far our third son, Dan, who is 19 and due to start at Sussex University in October, has ridden by bus to a full moon party, returned to Bangkok by "sleeper" train, gone jungle trekking, bought a bass guitar, lodged with a barman called Joe, bought a "pretty but tacky hammock" and ordered a cashmere suit which is, he assures us, "not a Khoa San Road special" but Thai government-subsidised elegance.
He is on a gap year, travelling with friends from his north London sixth form. Since sitting his A-levels last year, he has worked to raise money, first packaging Christmas orders at the Arsenal warehouse, then collecting direct-debit sign-ups for charity.
Six summers ago we received an airmail from Namibia every fortnight with tales of elephants in the wild, horse riding through mountains on trails used by Boer settlers and being the sweated labour helping to build a village school. That was when our eldest son, James, now graduated from Manchester University, was abroad with Raleigh, the youth development charity.
Earlier that year he had been in India, travelling independently with a friend. Then, the communications we received were mostly reverse-charged calls about a motorbike accident. He came back from Namibia with what he had not told us about; a video of his sky-dive during the two weeks of travelling after the official three months trip was over.
He funded the Indian travel by working as a waiter in West End hotels and Raleigh by doing a sponsored climb of a hospital tower and door-stepping local businesses, the Rotary Club and neighbours.
He had originally planned a gap year in Eastern Europe, working as an English assistant. Then he announced that he was considering Raleigh. We thought the tough endurance weekend Raleigh puts applicants through would weed him out, but crawling through freezing mud at 3am in Oxfordshire in January made him more determined. He says that he would recommend a gap year to anyone.
Our 17-year-old daughter, who is about to start a drama BTEC national diploma, is planning a gap year in two years. She has been besotted with elephants since we took her to a circus when she was two and she wants to find a gap charity which works with elephants in Africa.
Our middle son, Peter, who has just completed an art foundation course, chose not to take an official gap year because he had had two attempts at his A-levels and felt he had idled enough. He is enjoying a summer in London, saying that most of what he wants to discover is in his home city. His passion is contact juggling (a relatively new form of juggling where balls are rolled over the hands and body instead of tossing them in the air) and he has found workshops in Brixton and Highgate.
The communications we get from abroad are fun, but being parents backing gapping kids is hard work. There is an inevitable cost, if only their keep while they raise cash. We helped sponsor our first son and lobbed in a few bob for our second son to buy hammocks, but not more, arguably, than we would have provided had they been starting work and needed suits.
But there is also emotional wear and tear, being on the receiving end of the communications from abroad has gut-twisting moments. Picturing your offspring yelling with delight as they risk life and limb nurtures parental terror.
The upside is that we believe that our offspring were much better prepared for university. Today's undergraduates are light years more sophisticated than we were. There are parents who worry that if their children take gap years, they will not go back into education. There is a part of me that worries with them but I hang on to the belief that after a year out they will make better informed decisions. Bottom line, like the parent bird pushing out the fledgling, it is self-sustaining flight that we seek.